Developing legume shade trees for Sustainable coffee production in Puerto Rico

Developing legume shade trees for Sustainable coffee production in Puerto Rico

Summary

Coffee production in Puerto Rico is located in the central mountain region, mostly on acid, highly erodible soils. Many small and medium scale farmers have limited resources and use questionable practices. Long-term, sustainable coffee production using environmentally sound practices should include shade trees and, if possible, fast-growing, nitrogen fixing trees (FGNFT). In an effort to increase coffee production, sun grown coffee was promoted by the Agriculture Department. Unfortunately, this system of production requires high inputs and is environmentally damaging. To help coffee farmers, we will determine the best agroecological zone, evaluate legume trees species with potential for shade use, and determine management alternatives for high-quality, sustainable coffee production.

Objectives/Performance Targets

Objective 1. Survey present coffee production systems used by farmers in Puerto Rico

As indicated on the previous year report, the whole project is delayed about one year from the original schedule. The technical Research position was filled by M. Lionel Cruz (MS) and the graduate student carrying out research (MS Thesis) on this objective (Mr. Miguel Arango) have been doing extensive field work and data collection. Using the amount of coffee produced by municipality, the 20 highest producers were selected for field sampling. Combing the number of farms with shaded coffee with the map of coffee production area, coffee growers were located and interviewed. Each farm was sampled (1,000 sq meters plots) up to 5 acres or 2 plots for larger farms. In each plot, tree species were identified, measured for diameter at breast high (DBH) and tree high estimated. Plots were georeferenciated with GPS, and located in a GIS map, to correlate with soil map and altitude.

Objective 2. Evaluate the potential value of fast growing nitrogen fixing trees for the production of shade coffee.

The original list of potential trees for testing (Nitrogen fixation ability) has been reduced, since it has been impossible to obtain seeds from some rare species (see Accomplishments).

Accomplishments/Milestones

Objective 1.

Using the coffee farmer’s database compiled previously, field trips to all larger coffee producing municipalities and neighborhoods were taken. Over 110 farmers with shaded coffee have been sampled. Preliminary results indicate that more than 55 species (IVI, Index of Value Importance) with DBH> 10 cm are present. The predominant species found were Inga vera, Citrus sp., and Andira inermis, with 33.7%, 11.3% and 9.1% of IVI, respectively. The values for basal area (BA) were 36.5%, 5.8% and 7.0% in that order. The correlation between basal area and crown area (CA) was highly significant (r=0.48, P<0.0001). Clearly, coffee farmers select legume trees for shade and include a fruit species for additional income. Data for climate (Puerto Rico Climate Center) and soils of Puerto Rico (USDA-NRCS) have been obtained, digitized and prepared as excel data tables. A final map with agroecozones for coffee production will be developed by adding optimum ecological layers, soils and appropriate information using ArcGIS (v.9.1). The new map will substitute the present imprecise map of the coffee producing area, and could be used to give more incentives to farmers located in the best zone for coffee production. Management options for farmers (amount of shade, fertilization, tree species, etc) can also be deduced from this map. Objective 2. The two most extensive soils from the coffee region (Los Guineos and Humatas series; Oxisol and Ultisol respectively) were selected for the greenhouse experiments. They have been analyzed and both are acid and poor in available N). The greenhouse (6 kg of soil/pot) experiment with selected legume tree species is ongoing with a reduced number of species. This objective faces some problems due to the lack of seeds, since: 1. We had to wait for seed production for many local species in order to obtain seed. For some species we have not been able to locate trees producing, or their fructifying period is unknown. To facilitate future work and seed collection, we are preparing tables with species location (GPS) and the period of flowering/seed production.
2. Some species (mostly of the genus Inga), even when harvested in the most appropriate time, are recalcitrant and don’t germinate after 2 weeks in the best storage condition. Therefore, some of these species were included in the first, smaller experiment. For comparative purposes, seeds of Pithecellobium carbonarum (carbonero) were included as control, and they will be included in every planting date. However, this species that shows good shade characteristics was shown very susceptible to nematodes, at least in one soil.

Although the gas chromatograph (for the ARA analysis) purchased with the project funds has been installed in the laboratory (February 2006), we had problems with software, column and gases. We hope to solve the last problems in the near future and receive the appropriate training from the company (Agilent). Alternatively, the species that have been already harvested will be analyzed by Kjeldhal to estimate the amount of N fixed. Therefore, we can estimate that to complete the project, an extension without additional funds will be required.

Impacts and Contributions/Outcomes

1. A WEB page about the project (link to SARE) is available in the INTERNET at:

http://academic.uprm.edu/eschroder

(It is still under construction and will be updated).

2. Two new graduate students initiated in January 2006 their MS studies and will conduct their thesis within the SARE LS04-162 PROJECT (Glenny López, from the Dominican Republic and Ixia A. Avilés from Puerto Rico).
3. Data and results from the project have been presented at:
a) SOPCA Annual Scientific Meeting (Guaynabo, PR, November 2005), and
b) Seminar to students in Environmental Sciences (Interamerican University, Ponce, PR, February 2006).

An exhibit about Sustainable coffee production was displayed at the Agricultural students Agricultural Fair (5 Days with our Land, March, 2006).

Preliminary arrangements and some invitations have been made to organize the Sustainable Coffee Forum in May, 2007 (as proposed in the grant).

During this project, probably up to 4 graduate students will obtain their M.S. degrees and be trained in the production of sustainable coffee.

The major project outcome will be:
1) Identification of the best area for growing coffee in Puerto Rico (ecozoning) and
2) Farmers and extension agents will be able to select the best tree species for each soil and altitude.

However, due to the slow initial start and some of the administrative and scientific problems, an additional extension of one year for the grant (with no additional funds) is necessary.

Collaborators: